Prop shaft alignment Question

[Idon84]

Hello all,

I have an engine-mounting question that I need some help with.

Last weekend I finally got around to doing some eyeballing of my engine to the prop shaft alignment. I installed the old shaft and cutlass bearing then placed the engine on the new beds I installed(an engine pan from Cape George Marine Works). Generally what I find is that I need to be about ½” higher, even with adjusting the mounts to their highest point. Much more troubling however, is that I need to move the engine over to Port about 3/4”. Problem is that if I move her 3/4” to Port the Starboard engine mount now only sits part way on the mount and part way over the edge. (See Pictures attached) This mount has steel imbedded into it to tap the threads into, but there is no way I will be able to get them to line up to do that. The distance between the inner faces of the mounts and the inner faces of the mounts are almost exact leaving little room to move the engine port or starboard.

I have a few ideas I though I would kick around.

1. Use composite board (5/8” thick 1708 with epoxy) glued to the mount to raise the height, but this doesn’t fix the 5/8” to port issue unless I off set the board to hang over the edge to port a little and then fill with something…? (This method sounds messy, ugly and wasteful with epoxy)

2. Have custom mount brackets made. Have my local metal shop build me some new mounting brackets that are ½” taller and 5/8” to starboard. But what about increased leverage on these brackets that are now out of YANMAR spec (1/2” taller and 5/8” wider to starboard), would this be an issue?

3. Cut out the stern tube and start over. (not a very happy thought)

Thanks for the help,

[Skipper599]

Go with option #3 ... You'll never be happy with the other two options because like too many of us here, you're probably a "perfectionist" ... JMO ... besides which, that would be my approach.

[Tim]

I don't know how thick and long your deadwood and stern tube are, but I'd seriously consider the option of cutting out and replacing the stern tube to fix this issue.

I've found that other than dealing with a potentially long, deep hole, it's generally pretty easy to cut out an old stern tube, and installing the new one--which would then be in perfect alignment with your shaft and engine--is a snap. I've had good luck in the past using a hole saw to simply cut out (i.e. around) the old tube from the outside after first ramming some wood through the old tube to provide a point for the pilot bit; the biggest issue with this is bottoming out the hole saw frequently and dealing with that issue. A long Forstner bit might work well once you get the hole started. Again, I don't know how long your deadwood is. The longer it is, the more challenging this job.



You can easily deal with the height issue you have by installing a 1/2" or whatever fiberglass board on top of your existing foundations, as you suggest, unless you find it's easy to move the stern tube a corresponding amount. Painted up to match the rest of the area, you'll never notice. Of course, if your stern tube replacement can also address the height issue, so much the better.

This very sort of issue is why I vastly prefer building new foundations from scratch for any engine installation. I've had to do it both ways, and the couple times I've been forced to re-use existing foundations, I have run into annoyances and frustrations that could have been easily dealt with by building new from the getgo. As much work and layout as they require, this is generally the best and most accurate way to install any engine. Dealing with existing foundations, and pre-molded pans, frequently leads to this sort of issue, the resolution of which usually takes more time than simply building new when all is said and done, and is certainly more frustrating.

[Idon84]

Thanks all.

Not surprised at the suggestion and was fully prepared for it. Tim I have reveiwed your blogs on removal of the shaft and think I could do it. The depth is 16", pretty long.

Now the next question. Where does one find a good shaft log? Cape George has some that are made from what looks like very thick PVC pipe and then there are the bronze options from Buck Algonquin. What are some of the best options?

Thanks again,

[Tim]

I believe the bronze would be my choice.

This place makes some nice-looking stuff.

[Skipper599]

Generally speaking, I much prefer and have installed a bronze log ... Have you searched the various Marine Exchange stores for a good 'used' log? ... If that is not in your budget, Perhaps you might consider making one by f/g layup?
I know I've seen detailed instructions somewhere on line but can't remember which site. I'm sure a Google search would locate it.

[Quetzalsailor]

The 'PVC' log is probably FRP or fiberglass. Supposed to work fine.

The M 27 had knurled bronze, knurled for bond to the fiberglass. The Northeast 38 has a mating pair of honkin' bronze castings bolted through the 'rudder post'. The outside portion has the cutless and the inside mounts the reinforced hose.

[Tim]

If you're talking about the tube you need for penetrating your deadwood, there are some options.

Centek makes HD thick-wall FRP shaft log tubing, such as this available at Fisheries Supply.



Also Spartan Marine.



And then there's FRP and G-10 tubing from McMaster-Carr.

[Idon84]

Those are the GRP tubes I'm thinking of. These go just throught the dead wood portion? The version I saw at Cape George Cutters was a long tube that had about 5" on one end larger to accept the cutlass bearing.

I guess I'm a bit confused as to the anatomy of this part. I know it is a simple thing but looking at pictures and options gets me all confused. I like the way Tim's daysailor project turned out and would hope to have something like that but those bronze parts that Tim linked to above don't look like complete tubes. Do those parts simply hold the cutlass bearing while the GRP tube handles the shaft from there to inside the boat to the packing? Am I missing something? Please excuse my stupididy in this area, I've done a lot of boat projects but never anyting having to do with stuffing boxes & prop shafts.

Attached are some pictures of my old tube. It looks like a bonded in, 16" bronze tube that accepts a 3" long(way small) cutlass bearing in the end. With the bearing out you can feel a small lip 3" inside the tube to stop the bearing from going in to far. From what I can tell its all one part (bronze) all the way though. You can see the cutlass bearing in the lower picture still not removed.

[Idon84]

BTW... It's amazing how my anxiety goes away when I commit to a course of action even if I didn't like the thought of having to do the job anyway. So thanks all for the clear course to take. As a matter of fact, lining up the shaft by having the engine fixed and rebonding a tube puts me at ease even more.

Skipper599,

Go with option #3 ... You'll never be happy with the other two options because like too many of us here, you're probably a "perfectionist" ... JMO ... besides which, that would be my approach.

So TRUE! I couldn't imagine doing it any other way. Thanks!

[Idon84]

After more study, I think I have this all figured out. I'll just have to figure out what works best for my situation... off to cutting!

[Paulus]

then placed the engine on the new beds I installed,

One thing I don't quite understand is that you are going to re-allign the shaft to line up with a recently installed new engine bed?

Forgive me if this sounds flippant but would it not have been better to position the new bed in line with the prop shaft? That said, and given the current situation, in my humble opinion, I would prefer to make adjustments to the engine bed - even start from scratch and built one that is in-line, rather than redoing the whole stern tube.

But that is probably because I am really good with structural/fiberglass and I have never yet messed with stern tubes...

[Idon84]

Actually yes that would be the best method if you were smart enough in the beginning to realize it. Me however, not so much so. I bought the pre made engine pan from the manuafacturer and installed it according to their factory specs. I kicked the idea around of just building the mounts myself but opted for the pan instead. Thinking back now, I probably wouldn't do that again because of the issues just as Tim mentions above. Too late now.

I read all of the "engine install" portion manual last night and it reads pretty much like the install photos of Tim's Daysailor project... install pan, drill a 1/4" hole through the apature outside hull at 90degrees to the flat, then 12" through the deadwood to the dam then drill a 2 1/8" hole all the way through, insert tube and bond into place using milled fibers and silica with the engine mounted and shaft set up to give us the proper angle.. I can do this... can you tell I'm trying to psyching myself up?

At work can't edit images here to fit, here is a link: http://picasaweb.google.com/lh/photo/Yk ... directlink

[Paulus]

Ahem....

Just spent some time perusing the pictures of your TOTAL REBUILD... forgive me - my comments above were inappropriate.

Good luck with your project - hats off to you for taking all this on.

[Idon84]

No forgiving neccessary. The only dumb question is the one that isn't asked and the method you mention would have been much easier. Hopefully someone will read this thread and not do what I did.

Cheers,

[Skipper599]

Idon 84 ... I neglected to ask in previous posts ... What is preventing you from re-using the original Bronze Shaft Log??? .... Is it worn in some manner? ... Although I don't understand how it could be because theoretically, the moving shaft should never come in contact with the Log itself and so, the only other damage I can think of would be galvanic corrosion ... even that may well be repairable ... Have you checked with your local Machine Shop? ... maybe, it can be rejuvenated at a much lower cost than making a new one.

[Idon84]

True Bob, actually thought about that afterwards. I guess it would depend what kind of condition it would be in after I removed it.

One thing about this current tube I didn't like was that I can only put about a 2.5" long cutlass bearing into it. I don't know what kind of effect that would have. Having a little bit longer, 4" or so, cutlass seems to be a good idea. I may be totally wrong on this but who knows knows. Every cutlass bearing I've seen come out of a boat in the past were almost 2 times as long as mine.

I'll be sure to take lots of pictures & notes of the process to post them here in the future!

Thanks again for everyone's input!

[Skipper599]

How long is your shaft? If it's relatively short, you don't need a long Cutlass Brg. on the other hand, if you're going to be less than satisfied with what you currently have, it would be simple for your local machine shop to machine the inside of the Log to accept the longer one. All they are doing is removing more material from the current 'Stop' to position the step further inboard from the end.

[Idon84]

The specs for the shaft are 43" long. It may be possible to reuse the old one for sure. I'll have to see what can be done after I get the old shaft out. Getting the old one out, I expect, will be enough for my brain right now.

It may be possible to reuse the old one for sure. On the other hand, I've spent so much already rebuilding that I'm not totally turned off at the idea of something new, shiny & expensive either. Time will tell.

[Skipper599]

In the FWIW department, the cutlass brg. in my shaft log is 4" long whilst the 'bare' shaft is 30" ... this does not include the coupling. This shaft assembly was designed specifically for my boat (using a 12hp BMW engine), by Campbell Marine, of Vancouver,BC (manufacturer of shafts and props). It sports a "Campbell Sailer" prop. This patented 13" x 3 blade prop has 'cupped' trailing edges, designed to provide improved reverse thrust.

I doubt very much you have a need for a longer bearing yourself. If the original has shown no oddball type of wear and tear, why reinvent the wheel? Many of us tend to overbuild for the storm we'll never encounter. My advice would be, clean it up, install a new Cutlass brg. Polish it all too if that is what will make you feel better but, go with what you have and be happy.

[Zach]

If it was me, I would see if the lower half of the engine mounts come apart, or if the rubber is bonded to the steel. If the rubber is replaceable, I would weld a piece of 1/2 inch plate connecting both mounts on each side, and then slide the engine forward or aft an inch or two, and slot the 1/2 inch plate to make the adjustments needed to make everything work. Then again, I weld...

I reused a bronze shaft tube that was 68 years old and in perfect condition. I did put it inside a fiberglass tube to keep the ole wood boat it was in from weeping water damp around it... Fiberglass is easier to work with,unless the bronze is flanged as you can't use the outside of the sand casting for reference.

5/8ths is a lot when you talk about the skin thickness on your hull. I would take a set of calipers, or make a set with a few sticks (Just mark the position on a story board like you would a bevel gauge so you can reset the points to the same opening if the get bumped. Define how wide the hull gets, and then jam a stick the thickness you want to move over to port, along the length of the tube that is exposed. I would move the engine stringers, before grinding away a 40 inch strip of the hull laminate.

If you re-use your stuffing box on your used shaft... put it in a different spot. Most boats have a wear ring where the packing rides, think it through and make the shaft log just shorter or longer so that it makes your access easier and gives a fresh piece of shaft to work with.

If you choose to go fiberglass:

If you are on a budget, and want to go fiberglass... a single tube, that is the outside diameter of the cutlass bearing is easy to make. Go get a piece of PVC pipe that has the same inside diameter as the outside diameter of your cutlass bearing. Wax the PVC pipe, and lay up your cloth on the outside of the PVC. 1 or 2 layers thick, or around an 1/8th of an inch. Now take a metal cut off wheel on an angle grinder, and cut through to the PVC in a straight line across the top of the fiberglass tube. Now go get another piece of PVC, wax it... sand off the outside of your 1/8th inch thick tube... and then finish laying up your fiberglass tube to the desired thickness. A tube much longer than 2 feet, on a non-tapered form does not come of very easily at all. WIth only a thin seam gluing the fiberglass tube to the PVC, it is very easy to pull back apart. Most of the stuff on 60's stuff is just polyester resin and finish cloth wrapped around and around till the desired thickness is reached... You could have your tube for 20 bucks.

If you want it done the best you can... Buy 2 tubes. One that is the diameter of your shaft, the other will be larger and slip fit the small one inside epoxied in place. I haven't seen it mentioned, but thats the easy way to give a shoulder inside for the cutlass bearing to stop from going to far.


You buy a cutlass bearing that has the Inside Diameter of your shaft's OD. The outside diameter of the cutlass bearing, is the inside diameter of the large tube. Pick out your bearing before you decide what your wall thickness will be, if you've got a goofy size shaft. Noel has goofy shafts, take X11 zincs. 2 3/4 diameter... I always seem to find the last set in the county when its time to haul out.

Now you just cut the inside tube shorter than the outside one, by just a hair less than the length of your cutlass bearing so just a hair sticks out and no snot ring (technical term) can grow and make it real hard to get it back out when it is time to change.

Given you don't want to pull the engine again.... To do the alignment, you'll just want bolt the shaft coupling together, and support the weight of the end of the shaft at the prop side. Don't jack it up, just support it with a stick cut to the height it takes to take a little weight. Slide the fiberglass tube where it needs to go relative to the shaft and inject thickened epoxy (With cotton fiber) into the void. I use mylar packing tape to make a clear dam so I can see if there are air pockets. If you don't mix it up to peanut butter, it self levels and will let some of the air through. I use slow or tropical so the glue doesn't go atomic and move around...

You cannot use the shaft as the guide for the installation of a fiberglass tube, if the tube is a sloppy fit. You will have to do the string method, and at the very least build a jig that defines the centerline of the shaft coupling with a wide enough plate of plywood to define that your string is running perfectly perpendicular to the shaft flange. Otherwise, the engine will need to come out so you can build your pan, and pull the string through the centerline...

I like to have a flat plate, or flange on the shaft tube, so I can use a folding extension rule and get everything dialed in close without running back and forth up the ladder. Makes life easier... Put the factory end of the fiberglass tube on the inside of the boat.

I use a sawzall with a dull blade, and a piece of 40 or 60 grit sticky sandpaper on it to wallow out the hole in the dead wood. Works fast, and is easy as pie to do. A wooden dowel as big as will fit and long enough to pass through acts as a reamer works too, take a roll of inline paper and roll it like a candy cane with a layer or two. If its thick paper you may have to shoot some 3m 77 on the ends to get it to stay stuck.

Put an index mark on the tube so you put it in the same way every time. A bright light on the inside while you work from the outside will let you sight around the tube and see where there is contact, as will taking some black gel coat pigment and slathering up the end of the fiberglass tube, sliding it in and seeing where the mark transfers. Just make the hole big and speed up the process...

Once the shaft tube is in place and glassed in, unbolt the engine and re-align the engine to the shaft flange. No matter what method you choose to align the shaft, once the epoxy kicks... double check it and take everything loose one last time.

Cheers,

Zach

[Tim]

You cannot use the shaft as the guide for the installation of a fiberglass tube...

Sure you can, at least on the dinky little shafts and boats we're talking about here. All one needs to do for a successful and accurate alignment of the new tube perfectly with the engine is install the appropriate Cutless bearing and stuffing box to support the shaft within the tube while installing it.

[Zach]

Excellent point that!

The rest of my quote was that you can't use the shaft to align an oversized shaft tube... given there is just free floating air around it. Which is one of those points that is probably to obvious to point out. Grin.

But well stated...

Zach

[Idon84]

Finally got the stern tube removed. After a lot of going back and forth on how I would remove this long stern tube I decided to just buy a specialty tool to do that job. Other ideas on removing this may not have worked and would have ended up possibly costing more that the tool itself which was in the neighborhood of $200. I purchased it through Pipeman Products, http://www.pipemanproducts.com/

With the tool I was able to drill into 12" and completely remove the old tube(technically only needed 10" of depth). Now I have a 2 1/8" x 12" deep hole saw that I probably will never use again. Oh well, having this tool gave me great piece of mind.

Here I used the standard 2 1/8 hole saw to get the hole started.

Removed

The tool and the tube.

The hole inside.

[Skipper599]

Good job there Bryon, I'm sure you feel better now that you've done the right thing. Awesome tool too. I wasn't aware there was a hole saw that long. . . . As you say, you may never use it again so might I suggest you figure out a "rental" fee should anyone else want to borrow it? After all, it seems a shame that it should be used for only one job. If it was produced commercially, there MUST be a need for it. All you have to do is let it be known you have it available for a fee + S&H.

I guess the next move is to install the new Shaft Log. Did you buy new, or refurbish the original?

Good pictures by the way. The interior pic reminds me of the day I started work to install the Shaft Log on my bare Hull & Deck Kit . . . oh so many years ago. You even used the same grey gel-coat paint inside.

[Rachel]

Ahhhhh! That has to be a good feeling. Now you can go in with the new, all nice and aligned.

[Idon84]

As far as I'm concerned anyone can use it if they just want to pay for shipping & maybe a deposit. It is a really heavy duty saw and cut out my tube in less than 5 minutes. The guys I bought it from said if taken care of should last over 500 holes... So there are 499 left!

And YES it is a good feeling to finally have that all out of there. I stressed a lot thinking of how I would do this.

Because I tried a couple of other methods to remove the log, I ended up damaging the old log and most probably won't be reusing it.

I have many other questions on this job but they are a little of topic and I don't have all of my measurements yet. They mainly having to do with sourcing the log parts and finding out what my taper should be for my shaft to fit my Campbell Sailor Prop. I've used the formulas online but keep getting 13.337 as my number which is weird. I'm going to measure tonight in metric not standard. Seems a lot of things on this boat were metric.

Thanks again for all the info!

P.S. That grey paint is from Devoe Paints called BAR RUST 235. It's a 2 part epoxy coating meant for refurbishing old rusty hand rails and parts on stair cases etc. Also used as an concrete paint for garages etc. Makes an EXCELLENT bilge paint, very tough and chemical resistant. Takes FOREVER to sand through and of course, expensive!

[Idon84]

Here is a photo on the stern tube needed.

[Idon84]

Well, after looking around for tubing two things kept coming up. A lot of places wanted me to buy a minimum length of 10' or in some other cases I had to wait quite some time to get a 16" piece (Fisheries Supply in Seattle estimated 3 months!).

I called Todd at Cape George Marine works to see if he had any tubs sitting around and he did so I bought it. Standard tubing would have cost around $60, but this part from CGMW cost $125. Deal considering I don't have to worry about it anymore and it's even shaped to look like the old tube with setscrews and everything.

Skipper599, you wanted to know what I was going to use. See below.

[Skipper599]

Lookin' good Bryon, ... is that tube fibreglass?

[Idon84]

Yes it is. It looks like it is one large rectangular piece of cloth wetted out and rolled around something. There are about 7 layers of cloth in total all one piece. It's quite beefy.